The present invention relates to a magnetic disk apparatus, and more specifically to a magnetic disk apparatus equipped with a ramp loading mechanism.
In recent years, in the field of the electronic device such as a personal computer, a magnetic disk apparatus is widely used as a large-capacity memory device. In general, a magnetic disk apparatus comprises a magnetic disk arranged in a case, a spindle motor for supporting and rotating the magnetic disk, a head actuator for supporting magnetic heads, a voice coil motor for driving the head actuator, a substrate unit and the like.
The head actuator includes a bearing section set on the bottom of the case, a plurality of arms extending from the bearing section, and suspensions extending from the respective arms, and the magnetic heads are mounted on extending ends of the suspensions.
With regard to the magnetic disk apparatus described as above, there are two types of methods for holding the magnetic heads at a predetermined position while the apparatus is not in operation, that is, a so-called CSS (contact-start-stop) method for holding the magnetic heads on an inner circumference of the magnetic disk, and a ramp loading method for holding the magnetic heads apart from the surfaces of the magnetic disk by a ramp provided on the outside of the magnetic disk.
Meanwhile, in recent years, portable small-size personal computers are becoming popular, and there is a demand of improving the reliability of a magnetic disk device mounted in a personal computer of this type, against shocks and the like while being carried. Under these circumstances, in such magnetic disk devices, the application of a ramp loading method which can retain the magnetic heads more accurately is promoted.
In general, the ramp loading mechanism comprises a tab extending from the tip end of each suspension, and a ramp provided on the outside of the magnetic disk. When the magnetic disk device is not in operation, the head actuator is turned to the outer circumference of the magnetic disk, and the tab of each suspension move up the ramp. In this manner, the magnetic heads are held at a position away from the surfaces of the magnetic disk, thus preventing the collision of the heads against the magnetic disk, which might occur when the apparatus undergoes a mechanical shock.
In general, the ramp of a ramp loading mechanism is arranged such that a portion of the ramp overlaps with the outer circumferential portion of the magnetic disk. With this structure, that portion of the ramp which is situated between two adjacent magnetic disks, has an upper-side guide surface and a lower-side guide surface for guiding two magnetic heads, one on the upper side and the other on the lower side, respectively. These upper-side guide surface and lower-side guide surface are situated between magnetic disks in such a manner that these surfaces oppose to each other at a predetermined distance.
In order to unload the magnetic heads to a retreated position on the ramp, it is necessary to place the end of each guide surface of the ramp closer to the magnetic disk surface side than the corresponding tab of the suspension. Therefore, a gap between each end of the ramp and the surface of the magnetic disk is made very narrow.
With this structure, when assembling the magnetic disk apparatus, there is a high possibility of danger that a magnetic disk is brought into contact with the ramp, which may result in damaging the surface of the disk. Further, even after the assembly, there is a high possibility that the magnetic disk is brought into contact with the ramp when the apparatus undergoes a mechanical shock by some external force. Such possibilities are further raised as the number of magnetic disk mounted in the magnetic disk apparatus is increased.
Therefore, the distance between the ramp and the surface of a magnetic disk should preferably be made as wide as possible. However, as the density of the apparatus assembled is increased, the thickness of the magnetic head is decreased, or the distance between loaded disks is decreased, and therefore the distance between the surface of a magnetic disk and the ramp is shortened further. At the same time, there is an increasingly great demand of preventing damages to disks while assembling the apparatus, and improving the reliability of the apparatus against shocks. Under these circumstances, essential countermeasures are needed.
The present invention has been contrived in consideration of the above circumstances, and its object is to provide a reliability-improved magnetic disk apparatus in which the gap between a ramp and a surface of a magnetic disk is expanded without deteriorating its high-density mounting degree, so as to avoid contact between the ramp and the magnetic disk while assembling the apparatus or effected by some shock.
In order to achieve the above-described object, there is provided, according to the present invention, a magnetic disk device comprising: a plurality of magnetic disk provided at predetermined intervals; drive means for supporting and rotating the magnetic disks; a head actuator having a plurality of magnetic heads for recording/reproducing data on/from the magnetic disks, and a plurality of suspensions supporting the respective magnetic heads, for supporting the magnetic heads to be movable with respect to the magnetic disks; and a ramp loading mechanism for holding each of the magnetic heads at a position distant from the respective magnetic disk when the magnetic heads are moved to an outer circumference of the magnetic disks.
The ramp loading mechanism includes a ramp having a plurality of guides provided near the outer circumference of the magnetic disks and arranged at intervals between each other in an axial direction of the magnetic disks, and engagement members each provided at an end of the respective suspension, which is engaged with a guide of the ramp when the respective magnetic head is moved to the outer circumference of the respective magnetic disk, so as to pull up the respective magnetic head.
The head actuator includes two suspensions located between first and second magnetic disks opposing to each other. The ramp includes a first guide with which a first engagement member engages, the first engagement member extending from an end of the suspension located on the first magnetic disk side, of the two suspensions, and a second guide with which a second engagement member engages, the second engagement member extending from an end of the suspension located on the second magnetic disk side.
The first guide is located closer to the second magnetic disk than the second guide, and the second guide is located closer to the first magnetic disk than the first guide.
The first engagement member and the second engagement member are located on a center axis of the respective suspensions, and they respectively have first and second contact portions which are engageable with the first and second guides.
With the magnetic disk apparatus having the above-described structure, of a plurality of engagement members in the ramp loading mechanism, the first and second engagement members provided on the two suspensions located between the first and second magnetic disks which are adjacent to each other, are formed such that its up-and-down relationship is switched. Accordingly, the first and second guides of the ramp are arranged such that the positions of these guides are switched in the up-and-down direction. Therefore, the first and second contact portions of the first and second engagement members are made to pass through a gap between the surface of the magnetic disk and the ramp, thus decreasing the gap between the first and second guides. As a result, it becomes possible to assure a large interval between the guide of the ramp and the surface of the magnetic disk. Therefore, even if the number of magnetic disks mounted is increased, the interval between the ramp and the surface of the magnetic disk can be sufficiently maintained. In this manner, the contact between the ramp and a magnetic disk, which might occur while assembling or when the apparatus undergoes a shock, thus making it possible to improve the reliability.
Further, according to the magnetic disk apparatus of the present invention, the head actuator includes two suspensions located between first and second magnetic disks opposing to each other. The ramp of the ramp loading mechanism includes a first guide with which a first engagement member engages, the first engagement member extending from an end of the suspension located on the first magnetic disk side, of the two suspensions, and a second guide with which a second engagement member engages, the second engagement member extending from an end of the suspension located on the second magnetic disk side. The first guide is located closer to the second magnetic disk than the second guide, and the second guide is located closer to the first magnetic disk than the first guide. Furthermore, the first engagement member and the second engagement member respectively have first and second contact portions which are brought into contact with the first and second guides, respectively, and are provided to apart from each other by a predetermined interval in the direction of the movement of the magnetic heads. Thus, the first and second guides are provided to apart from each other by the predetermined interval in the direction of the movement of the magnetic heads.
In the magnetic disk apparatus having the above-described structure, the first and second engagement members are arranged to be apart from each other in the moving direction of the magnetic head, so as to avoid the interference between the first and second engagement members. Further, the first and second members corresponding to these are similarly arranged to be apart from each other by a similar interval in the moving direction of the magnetic head. With this structure, the two magnetic heads can be operated by the same load/unload timing. Thus, data can be recorded and reproduced efficiently without wasting a data recording area in the first and second magnetic disk.
Moreover, according to the magnetic disk apparatus of the present invention, the head actuator includes two suspensions located between first and second magnetic disks opposing to each other. The ramp of the ramp loading mechanism includes a first guide with which a first engagement member engages, the first engagement member extending from an end of the suspension located on the first magnetic disk side, of the two suspensions, and a second guide with which a second engagement member engages, the second engagement member extending from an end of the suspension located on the second magnetic disk side. The first guide is located closer to the second magnetic disk than the second guide, and the second guide is located closer to the first magnetic disk than the first guide.
Further, the first guide is projecting with respect to the surface of the second magnetic disk by a predetermined height, and extending such that the distance to the rotation center of the head actuator varies, whereas the second guide is projecting with respect to the surface of the first magnetic disk by a predetermined height, and extending such that the distance to the rotation center of the head actuator varies.
The first engagement member and the second engagement member respectively have first and second contact portions which are brought into contact with the first and second guides, respectively, and extend to be tilted with respect to the surfaces of the first and second magnetic disks, respectively.
With the magnetic disk apparatus having the above-described structure, the contact portions of the first and second engagement members are provided to incline. With this structure, the inclined portions of the guides can be omitted, and it becomes possible to further increase the distance between the surface of the magnetic disk and each guide.
Thus, according to the present invention, it is possible to provide a high-reliability magnetic disk with which the magnetic head can be accurately held at a predetermined retreated position, and the gap between the ramp and the surface of a magnetic disk is expanded without deteriorating the high-density mounting degree, thereby making it possible to prevent the contact between the ramp and the magnetic disk while assembling the apparatus or when the apparatus undergoes a mechanical shock.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.